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The present study explores the cleaning efficacy of a set of nonionic surfactants (linear ethoxylated alcohol, secondary ethoxylated alcohols with 5, 7, and 9 ethoxy groups, glycoside surfactants, polyglycerol surfactants, and an ethoxylated sorbitan monolaurate) combined with cationic biocides—alkyl quaternary ammonium salts. A simple hard surface cleaning methodology was applied, which was shown to discriminate well between poor and good cleaning formulations. In addition to cleaning efficacy, surface aesthetics such as gloss and haze were evaluated together to assess surface streaking caused by a residual surfactant layer. The haziness determination turned out to be the key feature revealing the complex cleaning performance of multi‐component products. [ABSTRACT FROM AUTHOR]

The main agent of clean fracturing fluid, cationic quaternary ammonium salt surfactant, is difficult to degrade in natural conditions because of its long alkyl chain. In this study, a biodegradable amphoteric surfactant, stearate sulfobetaine (SESB), was synthesized by esterification of long‐chain stearic acid and N,N‐dimethyl ethanolamine followed by quaternization to serve as the main agent of clean fracturing fluid. The structure of the synthetic degradable surfactant was verified by infrared and 1H‐nuclear magnetic resonance spectroscopies. In addition, a series of indoor performance evaluations were carried out, including shear resistance, viscoelasticity, sand carrying capacity, and gel‐breaking performance. A series of experimental evaluations showed that the clean fracturing fluid prepared with 2% SESB and 0.4% EDTA‐4Na had an excellent comprehensive performance. The apparent viscosity was higher than 50 mPa s at 80°C for a shear rate of 170 s−1. It has good heat and shear resistance performance. In addition, the system processed high shear stability and recovery at room temperature. According to the viscoelastic test, the system mainly relies on elasticity to carry sand. The static settling velocity of sand was 0.042 mm/s under high‐temperature conditions of 95°C. [ABSTRACT FROM AUTHOR]

The introduction of external CO2 could reversibly convert tertiary amines into quaternary ammonium salts, enabling demulsification/emulsification switching of emulsions or latexes. However, CO2‐switchable oligomeric or low‐molecular‐weight polymeric surfactants are rarely researched. In this study, 2‐(dimethylamino)ethyl methacrylate and stearyl methacrylate are chosen to synthesize a switchable oligomeric surfactant (OS). The conductivity of OS aqueous solution (0.2 wt%) increased from 14.0 to 329 μS cm−1 by adding and removing CO2, which proved a good performance of OS in response to the CO2 stimulus. The most important finding was that the crude oil emulsion containing OS was reversibly degraded and re‐formed by the alternate CO2 and N2 treatment. In contrast to that, the investigated PS latex system underwent apparent stratification after the N2 bubbling, but it regained a homogeneous phase upon the N2 bubbling. The particle size of PS latex varied between 245 nm and 130 μm, and zeta potential changed from −43.2 to −5.8 mV, which demonstrated that the PS latex stability might break and recover by addition and removal of CO2. This work is expected to open a new window for the CO2‐stimulated reversible emulsification of emulsions or polymer latexes. [ABSTRACT FROM AUTHOR]

A series of novel hydroxylated cardanol quaternary ammonium salts (HCQAS 3a–3g) with one or two hydroxyl groups, derived from renewable cardanol, a plant‐based and low‐cost material natural cashew nut shell liquid (CNSL), have been rationally designed and investigated as additive in detergent. CMC, γCMC, C20, pC20, and CMC/C20 were employed to exhibit the surface properties of HCQAS, reflecting that the surfactivity were superior to general cationic surfactants. In addition, HCQAS revealed excellent water solubility and wettability by krafft point and contact angle tests. Moreover, emulsifiability and foamability conversions were monitored versus time and volume of foam, respectively. Also, TEM micrographs were taken to provide the aggregation morphologies of HCQAS 3a aqueous solution at different concentration. Furthermore, HCQAS 3a and BGF‐10 binary composite system as well as HCQAS 3a, BGF‐10, and SDBS ternary composite system were investigated by CMC, γCMC, emulsifiability, and foamability to determine the optimum molar ratio (HCQAS 3a: BGF‐10: SDBS = 0.24:0.36:0.4), and then, analysis of morphology by TEM showed that the incorporation of HCQAS 3a, BGF‐10, and SDBS in aqueous solution accelerated the formation of abundant vesicles with large volume and surface area. Finally, a green concentrated detergent was designed and prepared with the filtered ratio, where the presence of vesicles greatly enhanced detergency to promisingly replace the familiar use of petroleum‐based TX‐10 in detergent. This study on the structure and performance of HCQAS may shed some light on the development of novel environmentally friendly surfactant. [ABSTRACT FROM AUTHOR]

Bola‐type quaternary ammonium salt can bridge with two fatty acid soaps through electrostatic attraction to form a pseudogemini surfactant, which enhances the solution viscosity. In this work, the effects of the building blocks (spacer and hydrophobic chain) of a pseudogemini surfactant on the Krafft temperature, critical micelle concentration, and rheological properties were investigated. The results revealed that the addition of bola‐type salt obviously decreased the Krafft temperature of sodium stearate (C18ONa), and a bola‐type salt bearing a large benzene ring (Bola2be) was more effective than the one bearing an ethyl group (Bola2et) or a hydroxyethyl group (Bola2hy). When bola‐type salt is mixed with fatty acid soap at a fixed molar ratio of 1:2, a pseudogemini surfactant forms in situ, and the viscosity of the solution is significantly enhanced by the formation of a worm‐like micelle (WLM) network. The stronger the hydrophobicity of the bola‐type salt or the tail of the fatty acid soap, the lower the critical overlapping and micelle concentrations, and the stronger is the ability to enhance viscosity. However, pseudogemini surfactants that use sodium stearate as a monomer show similar self‐assembly abilities to those using sodium oleate as a monomer. In addition, the WLM formed by pseudogemini surfactants composed of Bola2be and sodium stearate or sodium oleate were liable to branch at high concentrations. [ABSTRACT FROM AUTHOR]

The self-aggregation of sodium dodecylsulphate (SDS), an anionic surfactant, in aqueous solutions of tetraalkylammonium bromide salts (RNBr, where R = propyl, butyl and pentyl) was determined at various temperatures in the range 288.15-318.15 K. The critical micelle concentration (CMC) determined from conductivity data was used to study the thermodynamics of the surfactant. The presence of bromide salts was found to affect the micellization of SDS in accordance with the hydrophobicity of the tetraalkylammonium cations, thus the CMC values follow the order no additive > PrNBr > BuNBr > PenNBr. The results from conventional conductivity methods were combined with those of spectroscopic techniques like fluorescence and UV-Vis studies. [ABSTRACT FROM AUTHOR]

The surface activities and application properties of didecyldimethylammonium formate (DDAF) and sodium fatty alcohol ether carboxylate (AEC-9Na) mixed systems were measured. The results showed that the critical micelle concentration and surface tension of mixed systems have lower values than that of a single surfactant solution, which is attributed to the synergism of DDAF and AEC-9Na. It was found that the emulsifying properties for kerosene and wetting properties of the mixed systems were also better than single component surfactants. In addition, the mixed systems of AEC-9Na (16 wt%) with DDAF showed both better detergency and excellent antibacterial properties. [ABSTRACT FROM AUTHOR]

New alkyl hydroxyethyl imidazoline salts were synthesized via a high pressure process with imidazoline and dimethyl carbonate, and their chemical structure were confirmed using mass spectral fragmentation and FTIR spectroscopic analysis. In addition, several quaternary ammonium salts with new counterions (formic acid, acetic acid and lactic acid) were also synthesized by ion exchange reaction of methyl carbonate quaternary ammoniums with the corresponding acids. These new compounds reduced the surface tension of water to a minimum value of approximately 27 mN m at a concentration of 8.72 × 10 mol L. They also show efficient corrosion inhibition performances and could significantly inhibit the corrosion of mild steel in acid solutions. It was also found that the biological degradation of these imidazoline surfactants was greater than 98 % after 7 days. [ABSTRACT FROM AUTHOR]

Imidazoline-based dissymmetric bis-quaternary ammonium salt (DBA), a type of environmentally friendly surfactant, was compounded with thiourea (TU). The inhibition properties of the compound inhibitor for Q235 steel in a simulated oil field that produced water saturated with CO at high temperature were studied by weight loss measurement, polarization curves, cyclic voltammetry, electrochemical impedance spectroscopy, and observation of surface morphology. Weight loss measurements show that DBA alone has poor inhibition efficiency at high temperature, and TU has a narrow inhibition concentration range. However, DBA and TU together show a synergistic effect, which not only overcomes the short comings when used individually, but also significantly reduces the corrosion rate at reduced dosage. DBA-TU acts as a mixed prohibition inhibitor, and can rapidly form a protective film. The inhibition efficiency decreased slowly with soaking time, which shows it has good substantivity. In conclusion, DBA-TU can be used as high temperature corrosion inhibitor against CO corrosion. [ABSTRACT FROM AUTHOR]

A novel class of organosilicon gemini quaternary ammonium surfactant alkyl- α, ω-bis(diethyl-methyl-dimethoxy-silopropyl ammonium bromide) ( α, ω = 1,4; 1,6; 1,8) was synthesized and characterized by H-nuclear magnetic resonance (NMR) and elemental analysis. It is found that the quaternization reaction has two steps: first single quaternization and then double quaternization. The effect of solvent on convert ratio has the following sequence: polar aprotic solvents > polar protic solvents > aromatic solvents. The electrical conductivity of aqueous solution was measured at 20, 25, 30 and 35 °C, and the thermodynamic properties of $$ \Delta H_{m}^{0} $$ , $$ \Delta G_{m}^{0} $$ and $$ T\Delta S_{m}^{0} $$ were calculated according to the mass action model and Gibbs equation. It is shown that the enthalpy driven and entropy driven are almost equal in the micellization of [SiC-4-SiC]Br and [SiC-6-SiC]Br, but in the micellization of [SiC-8-SiC]Br, the enthalpic contribution becomes significant and the effect of thermal is greater than the degree of order in the micellization. [ABSTRACT FROM AUTHOR]

The rheological properties and time effect of a quaternary ammonium salt gemini surfactant C-s-C•2Br solution were measured. The rheological properties were markedly different at various concentrations of the surfactant C-2-C•2Br solutions. When the alkyl chain of C-2-C•2Br solution is 14 or 16, the rheological properties of the solution exhibit fluid dilatancy very similar to C-2-C•2Br solutions. However, when the length of the spacer is four or six, C-s-C•2Br solutions exhibit Newtonian fluid behavior and are quite different from the C-2-C•2Br solution. A C-2-C•2Br solution at a high concentration shows negative thixotropy and time dependency. [ABSTRACT FROM AUTHOR]

In order to improve the hydrolysis resistant ability (HRA) of trisiloxane surfactants, a new kind of quaternary ammonium salt cationic trisiloxane surfactant (QASCTSS) was synthesized in three steps and investigated. The chemical structure of QASCTSS was characterized by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance. Compared with normal trisiloxane surfactants, QASCTSS exhibits a lower surface tension, especially under strong acid or alkaline conditions. This was attributed to the protection for Si-O backbone from the quaternized side chain, and some improvement in HRA is seen in acidic conditions with ethyl instead of methyl side chains on the quaternary structure. [ABSTRACT FROM AUTHOR]

The Krafft temperatures, surface tensions and bacteriostatic efficacies of a series of dodecyl/tetradecyltrimethylammonium salts with new type counterions based on the general formula RN(CH) A were measured. The results revealed that the Krafft temperatures of the studied products were below 0 °C and the surface tensions of water were decreased to 22-42 mN m when applying these surfactants at a concentration range from 10 to 10 mol L. Moreover, the physicochemical parameters such as the saturation adsorption value, the minimum area per surfactant molecule and the standard thermodynamic parameters of adsorption and micellization varied with different counterions for these prepared quaternary ammonium salts. In addition, the bacteriostatic tests showed that the counterions with shorter carbon chain lengths were associated with greater efficacy for the novel quaternary ammonium salts studied here. [ABSTRACT FROM AUTHOR]

Three novel quaternary ammonium salt cationic gemini surfactants (QAS C- 2- C where n represents the hydrocarbon chain lengths of aliphatic amine, i.e., 6, 8, 12) were synthesized from 2,4,6-trichloro-1,3,5-triazine, ethylenediamine, N, N-dimethylpropane-1, 3-diamine and benzyl chloride. H-NMR, C-NMR, ESI-MS spectra and elemental analysis were used to confirm the chemical structures of the prepared compounds. Their critical micelle concentrations (CMC) in the aqueous solutions were determined by surface-tension, electrical conductivity and steady-state fluorescence methods respectively. With the increasing length of the hydrophobic chain, the values of their CMC decreased. The values of CMC, γ, pC, Г, and A were derived from surface tension measurements, while the thermodynamic parameters of micellization (∆ G and ∆ G) were determined by electrical conductivity. These properties are significantly influenced by the hydrophobic chain length. [ABSTRACT FROM AUTHOR]

Novel iminium compounds namely p-benzylidene benzyldodecyl iminium chloride (I), p-benzylidene benzylhexadecyl iminium chloride (II), p-benzylidene benzyloctadecyl iminium chloride (III) were prepared and characterized using FTIR, H-NMR and mass spectroscopy. The surface properties such as surface and interfacial tension, and biological activity of these surfactants were investigated. The surface parameters including critical micelle concentration, maximum surface excess, and minimum surface area. Efficiency and effectiveness were calculated, as well as free energies of micellization and adsorption. The prepared cationic surfactants exhibit a better biological activity than the used reference cetyl trimethyl ammonium bromide. [ABSTRACT FROM AUTHOR]

A novel series of mono-quaternary ammonium salts was prepared by the reaction of fatty esters of methyldiethanolamine with epichlorohydrin in the presence of amine hydrochloride. The ease of the reaction with epichlorohydrin was found to be due to the assistance of amine hydrochloride in opening the epoxide ring and to neighboring-group participation by the hydroxyl group of the mono-ammonium salt in the quaternization step. The surface properties of the prepared compounds and their biological activities were measured. The prepared compounds had good water solubility and showed characteristic surface active properties. [ABSTRACT FROM AUTHOR]

Two series of quaternary cationic surfactant were synthesized by reaction of 8-hydroxyquinoline and 2-hydroxypyridine with long chain alkyl halides (dodecyl, tetradecyl- and hexadecyl-bromide). Surface tension was measured in aqueous solution for different concentrations at 25 °C. Various surface properties of the synthesized surfactants were evaluated, particularly critical micelle concentration (CMC), efficiency (ΠCMC) as well as maximum surface excess (Γmax) and minimum surface area ( A min). Micellization and adsorption in liquid/air interfaces thermodynamics were investigated. The synthesized cationic surfactants were evaluated for their biocidal activity. All compounds prepared showed good antibacterial and antifungal activities. [ABSTRACT FROM AUTHOR]

Triethanolamine (TEA)-based esterquat has been the primary ingredient in European fabric softeners for several years and is becoming the global molecule of choice. Although it has an excellent environmental profile, TEA esterquat has been plagued by mediocre performance compared to historical molecules such as dihydrogenated tallow dimethyl ammonium chloride and ditallow imidazoline quat. In this study, the chain lengths, the level of unsaturation, and the source of the raw material (tallow or palm stearine) were varied to better understand their effect on softening and dispersion viscosity. Palm stearine derivatives generally soften as well as tallow derivatives despite the lower C18 content of palm. Various additives were examined to improve dispersibility and other properties such as dye transfer inhibition (DTI) and ease of ironing. DTI is normally accomplished in the wash cycle by additives to the laundry detergent such as polyvinylpyrrolidone. In this study, we found that fabric softener molecules themselves provide some color care, or DTI. Certain additives to fabric softeners, such as monoalkylquats, greatly enhance the color care of the fabric. DTI treatment in the rinse cycle of the washing sequence makes more sense scientifically and to the consumers, since fabric softeners are designed to coat the textile. Because no competing detergency operations are occurring during the rinse cycle, color care works well in the fabric softener cycle. Addition of organosilicones to fabric softeners reduces wrinkling of fabrics and makes them easier to iron. Softening increases slightly. [ABSTRACT FROM AUTHOR]